Mild neurocognitive disorder

Essential (Required) Features:

• Presence of mild impairment in one more or cognitive domains (e.g., attention, executive function, language, memory, perceptual-motor abilities, social cognition) relative to expectations for age and general premorbid level of neurocognitive functioning.
• Impairment represents a decline from the individual’s previous level of functioning.
• Neurocognitive impairment is not severe enough to significantly interfere with an individual’s ability to perform activities related to personal, family, social, educational, and/or occupational functioning or other important functional areas.
• Evidence of mild neurocognitive impairment is based on:
• Information obtained from the individual, informant, or clinical observation; and
• Objective evidence of impairment as demonstrated by standardized neuropsychological/cognitive testing or, in its absence, another quantified clinical assessment.
• Neurocognitive impairment is not attributable to normal aging.
• Neurocognitive impairment may be attributable to an underlying acquired Disease of the Nervous System, a trauma, an infection or other disease process affecting the brain, use of specific substances or medications, nutritional deficiency or exposure to toxins, or the etiology may be undetermined.
• The symptoms are not better explained by another Neurocognitive Disorder, Substance Intoxication or Substance Withdrawal, or another mental disorder (e.g., Attention Deficit Hyperactivity Disorder or other Neurodevelopmental Disorder, Schizophrenia or Other Primary Psychotic Disorder, a Mood Disorder, Post-Traumatic Stress Disorder, a Dissociative Disorder).

Note: Cases referred to elsewhere as Mild Cognitive Impairment (MCI) are referred to in the ICD-11 as Mild Neurocognitive Disorder (MND). When Mild Neurocognitive Disorder is due to a disease, condition or injury classified elsewhere (including Disorders Due to Substance Use), the diagnostic code corresponding to that disease, condition or injury should assigned in addition to Mild Neurocognitive Disorder. When the etiological condition is unknown, the diagnosis 8A2Z Disorders with Neurocognitive Impairment as a Major Feature, Unspecified may be assigned in addition to Mild Neurocognitive Disorder.

Potentially Explanatory Medical Conditions (examples):

In addition to any of the specified causes of Dementia, Mild Neurocognitive Disorder may be caused by:

• Anaemias or Other Erythrocyte Disorders
• Certain Infectious or Parasitic Diseases (e.g., meningitis)
• Diseases of the Circulatory System (e.g., coronary atherosclerosis)
• Diseases of the Nervous System (e.g., cerebral palsy, epilepsy or seizures, hypertensive encephalopathy, hypoxic-ischaemic encephalopathy)
• Endocrine Diseases (e.g., diabetes mellitus, hypothyroidism)
• Intracranial injury
• Metabolic Disorders (e.g., hypo-osmolality or hyponatraemia)
• Neoplasms of the brain or central nervous system
• Nutritional Disorders (e.g., vitamin B12 deficiency)

Additional Clinical Features:

• Mild declines in complex activities may be typically present (e.g., using transportation, meal preparation), while basic activities of daily living (e.g., dressing, bathing) are preserved. The individual may engage in compensatory strategies to maintain independence in everyday functioning.
• Behavioural and psychological symptoms are commonly associated with Mild Neurocognitive Disorder (e.g., depressed mood, sleep disturbance, anxiety).

Boundary with Normality (Threshold):

• Normal aging is typically associated with some degree of cognitive change. A diagnosis of Mild Neurocognitive Disorder does not apply if performance is consistent with expectations for the individual’s age, based on age-related norms for performance on standardized assessment.

Course Features:

• The course of neurocognitive impairment in Mild Neurocognitive Disorder may be static, progressive, or may resolve or improve depending on the specific etiology and available treatment options.
• In some cases, Mild Neurocognitive Disorder may represent an early presentation of an underlying Disease of the Nervous System that may later meets the diagnostic requirements for Dementia.

Developmental Presentations:

• Mild Neurocognitive Disorder can occur at any point across the lifespan with risk and prevalence depending on the underlying etiology. Overall risk for Mild Neurocognitive Disorder increases with age because of the increased prevalence of possible causal conditions.

Culture-Related Features:

• Performance during clinical assessment may vary according to cultural and/or linguistic factors. When assessing impairment in neurocognitive functioning and activities of daily living, cultural and linguistic factors should be considered and accounted for when possible.
• When standardized neuropsychological/cognitive testing is utilized for determination of neurocognitive impairment, performance should be measured with appropriately normed, standardized tests. In situations where appropriately normed and standardized tests are not available, assessment of neurocognitive functioning requires greater reliance on clinical judgment. (See General Cultural Considerations for Neurocognitive Disorders for additional information and examples.)

Boundaries with other Disorders and Conditions (Differential Diagnosis):

• Boundary with Delirium: Delirium is characterized by a disturbance of attention, orientation, and awareness with transient symptoms that may fluctuate depending on the underlying causal condition or etiology. Delirium typically presents with significant confusion or global neurocognitive impairment, in contrast to Mild Neurocognitive Disorder, in which there is mild impairment in one or more cognitive domains that does not significantly interfere with functioning.
• Boundary with Amnestic Disorder: Amnestic Disorder is characterized by prominent memory impairment relative to expectations for age and general premorbid level of neurocognitive functioning that is severe enough to result in significant impairment in personal, family, social, educational, occupational, or other important areas of functioning, in the absence of other significant neurocognitive impairment. While specific presentations of Mild Neurocognitive Disorder may primarily affect memory, the memory impairment is not severe enough to significantly interfere with functioning in everyday skills and tasks.
• Boundary with Dementia: Dementia is characterized by marked impairment in two or more cognitive domains that is severe enough to cause significant impairment in personal, family, social, educational, occupational, or other important areas of functioning. Neurocognitive deficits in Mild Neurocognitive Disorder may be in similar areas, but are not severe enough to cause significant impairment in functioning
• Boundary with mild cognitive symptoms in other mental disorders: Mild cognitive symptoms may be a characteristic or associated feature of a wide range of mental disorders (e.g., Attention Deficit Hyperactivity Disorder, Schizophrenia or Other Primary Psychotic Disorders, Mood Disorders, Anxiety or Fear-Related Disorders, Post-Traumatic Stress Disorder, Dissociative Disorders). If the neurocognitive impairment is better explained by another mental disorder, an additional diagnosis of Mild Neurocognitive Disorder should not be assigned.
• Boundary with Sleep-Wake Disorders: Memory and other neurocognitive impairment is frequently reported by individuals with sleep disturbance or Sleep-Wake Disorders, such as insomnia and sleep apnea. If the neurocognitive impairment is better explained by a Sleep-Wake Disorder, an additional diagnosis of Mild Neurocognitive Disorder should not be assigned.